MS8A Revision Questions

On a hot day, the pressure of the air in a car tyre is greater than on a cold day. Why is the pressure greater on a hot day?

D The number of air molecules in the tyre increases.

• The air molecules strike each other more frequently.

• The air molecules strike each other with greater force.

• The air molecules strike the tyre walls more frequently.

• The number of air molecules in the tyre increases.

Which statement defines the thermal capacity (heat capacity) of a solid body?

• the energy needed to melt the body without a change in temperature

• the energy needed to raise the temperature of the body by one degree Celsius

• the increase in the volume of the body when its temperature is raised by one degree Celsius

• the total amount of internal energy in the body

A substance can exist in three different states: solid, liquid or gas. Each of the two statements below describes a change of state.

change 1 Molecules move closer together but continue to travel throughout the substance.

change 2 Molecules stop travelling throughout the substance and just vibrate about fixed positions.

Which changes of state do these statements describe?

• A

• B

• C

• D

Ice is trapped by a piece of wire gauze at the bottom of a tube containing water. The water at the top of the tube boils before the ice at the bottom of the tube melts.

Why does this happen?

• Convection currents are circulating throughout the water.

• Ice is a poor emitter of thermal energy.

• Water is a poor conductor of thermal energy.

• Wire gauze is a good conductor of thermal energy.

It is a warm and humid day. A glass contains an iced drink. Water starts to form on the outside of the glass.

What is the name of the effect by which the water forms?

• condensation

• conduction

• convection

• evaporation

Four identical metal plates are painted either black or white and have either a dull or a shiny surface. They are heated to the same temperature. Which plate radiates thermal energy at the greatest rate?

• the plate that is dull and black

• the plate that is dull and white

• the plate that is shiny and black

• the plate that is shiny and white

A cotton sheet is ironed with a hot electric iron.

How is energy transferred through the metal base of the iron to the sheet?

• by conduction only

• by convection only

• by radiation only

• by convection and radiation only

A solid is heated from room temperature. The graph shows how its temperature changes with time as it is heated constantly.

At which time has it just become completely liquid?

• A

• B

• C

• D

The diagram shows a block of ice placed in a warm room.

At which point is the temperature the lowest?

• A

• B

• C

• D

Which statement about the transfer of thermal energy is correct?

• All metals conduct thermal energy equally well.

• Convection can only occur in solids or liquids.

• Convection occurs in liquids because hot liquid is more dense than cold liquid.

• The radiation that transfers thermal energy is a type of electromagnetic radiation.